Under a Microscope
If you get a studded
ring or a loose
diamond placed under a stereo binocular microscope for your perusal, do not pass that up at any cost. This would at least be a great experience even if you decide not to buy.
10x Magnification
This is the industry standard and came to be used as a result of the
Clarity Rating Scale, which too is a common standard these days in jewelry sales.
Lighting
When examining a
diamond, the lighting it is under can affect the way in which
it appears. For example, a laboratory light would remove all color except for what the
stone actually possesses. This is why you would need to view it under different light sources to determine whether it has what you are looking for.
Check for any problem with
clarity, because that is where magnification helps the most. See if there are internal markings that make the
stone look bad in any way.